Liquid crystal composition and liquid crystal display device

ABSTRACT

Providing a liquid crystal composition satisfies at least one of characteristics like a high maximum temperature of a nematic phase, a low minimum temperature of the nematic phase, a small viscosity, a suitable optical anisotropy, a large negative dielectric anisotropy, a large specific resistance, a high stability to ultraviolet light and a high stability to heat or has a suitable balance regarding at least two of the characteristics. Providing an AM device has a short response time, a large voltage holding ratio, a large contrast ratio, a long service life and so forth. The liquid crystal composition has a negative dielectric anisotropy and contains a specific compound having large negative dielectric anisotropy as a first component, a specific three-ring compound having large optical anisotropy as a second component and a specific two-ring compound having low viscosity as a third component, and a liquid crystal display device contains the composition.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a 371 of international application of PCTapplication serial no. PCT/JP2010/063823, filed on Aug. 16, 2010, whichclaims the priority benefit of Japan application no. 2009-193786, filedon Aug. 25, 2009. The entirety of each of the above-mentioned patentapplications is hereby incorporated by reference herein and made a partof this specification.

TECHNICAL FIELD

The invention relates to a liquid crystal composition mainly suitablefor use in an active matrix (AM) device and so forth, and an AM deviceand so forth containing the composition. More specifically, theinvention relates to a liquid crystal composition having a negativedielectric anisotropy, and a device that contains the composition andhas a mode such as an in-plane switching (IPS) mode, a verticalalignment (VA) mode or a polymer sustained alignment (PSA) mode.

BACKGROUND ART

In a liquid crystal display device, a classification based on anoperating mode for liquid crystals includes a phase change (PC) mode, atwisted nematic (TN) mode, a super twisted nematic (STN) mode, anelectrically controlled birefringence (ECB) mode, an opticallycompensated bend (OCB) mode, an in-plane switching (IPS) mode, avertical alignment (VA) mode and a polymer sustained alignment (PSA)mode. A classification based on a driving mode in the device includes apassive matrix (PM) and an active matrix (AM). The PM is furtherclassified into static, multiplex and so forth, and the AM is classifiedinto a thin film transistor (TFT), a metal insulator metal (MIM) and soforth. The TFT is further classified into amorphous silicon andpolycrystal silicon. The latter is classified into a high temperaturetype and a low temperature type according to a production process. Aclassification based on a light source includes a reflective typeutilizing a natural light, a transmissive type utilizing a backlight anda transreflective type utilizing both the natural light and thebacklight.

The devices contain a liquid crystal composition having suitablecharacteristics. The liquid crystal composition has a nematic phase.General characteristics of the composition should be improved to obtainan AM device having good general characteristics. Table 1 belowsummarizes a relationship between two of the general characteristics.The general characteristics of the composition will be explained furtherbased on a commercially available AM device. A temperature range of thenematic phase relates to a temperature range in which the device can beused. A preferred maximum temperature of the nematic phase is about 70°C. or higher and a preferred minimum temperature of the nematic phase isabout −10° C. or lower. A viscosity of the composition relates to aresponse time in the device. A short response time is preferred fordisplaying moving images on the device. Accordingly, a small viscosityin the composition is preferred. A small viscosity at a low temperatureis further preferred.

TABLE 1 General Characteristics of Composition and AM Device GeneralCharacteristics of General Characteristics of No Composition AM Device 1wide temperature range of a nematic wide usable temperature range phase2 small viscosity ¹⁾ short response time 3 suitable optical anisotropylarge contrast ratio 4 large positive or negative dielectric lowthreshold voltage and anisotropy small electric power consumption largecontrast ratio 5 large specific resistance large voltage holding ratioand large contrast ratio 6 high stability to ultraviolet light longservice life and heat ¹⁾ A liquid crystal composition can be injectedinto a liquid crystal cell in a shorter period of time.

An optical anisotropy of the composition relates to a contrast ratio inthe device. A product (Δn×d) of the optical anisotropy (Δn) of thecomposition and a cell gap (d) in the device is designed so as tomaximize the contrast ratio. A suitable value of the product depends ona type of the operating mode. The suitable value is in the range ofabout 0.30 micrometer to about 0.40 micrometer in a device having the VAmode, and in the range of about 0.20 micrometer to about 0.30 micrometerin a device having the IPS mode. In the above case, a composition havinga large optical anisotropy is preferred for a device having a small cellgap. A large absolute value of a dielectric anisotropy in thecomposition contributes to a low threshold voltage, a small electricpower consumption and a large contrast ratio in the device. Accordingly,the large absolute value of the dielectric anisotropy is preferred. Alarge specific resistance in the composition contributes to a largevoltage holding ratio and a large contrast ratio in the device.Accordingly, a composition having a large specific resistance, at roomtemperature and also at a high temperature in an initial stage, ispreferred. A composition having a large specific resistance, at roomtemperature and also at a high temperature after using the device for along time, is preferred. Stability of the composition to ultravioletlight and heat relates to a service life of the liquid crystal displaydevice. In the case where the stability is high, the device has a longservice life. Such characteristics are preferred for an AM device usedin a liquid crystal projector, a liquid crystal television and so forth.

A composition having a positive dielectric anisotropy is used for an AMdevice having the TN mode. On the other hand, a composition having anegative dielectric anisotropy is used for an AM device having the VAmode. A composition having a positive or negative dielectric anisotropyis used for an AM device having the IPS mode. A composition having apositive or negative dielectric anisotropy is used for an AM devicehaving the PSA mode. Examples of the liquid crystal composition havingthe negative dielectric anisotropy are disclosed in the following patentliteratures No. 1 to No. 6.

CITATION LIST Patent Literature

-   Patent literature No. 1: EP 474062A.-   Patent literature No. 2: JP H2-503568 A.-   Patent literature No. 3: JP 2006-37053 A.-   Patent literature No. 4: JP 2006-37054 A.-   Patent literature No. 5: JP 2006-233182 A.-   Patent literature No. 6: JP 2007-39639 A.

A desirable AM device has characteristics such as a wide temperaturerange in which a device can be used, a short response time, a largecontrast ratio, a low threshold voltage, a large voltage holding ratioand a long service life. A shorter response time even by one millisecondis desirable. Thus, desirable characteristics of a composition include ahigh maximum temperature of a nematic phase, a low minimum temperatureof the nematic phase, a small viscosity, a suitable optical anisotropy,a large positive or negative dielectric anisotropy, a large specificresistance, a high stability to ultraviolet light and a high stabilityto heat.

SUMMARY OF INVENTION Technical Problem

One of the aims of the invention is to provide a liquid crystalcomposition satisfying at least one of characteristics such as a highmaximum temperature of a nematic phase, a low minimum temperature of thenematic phase, a small viscosity, a suitable optical anisotropy, a largenegative dielectric anisotropy, a large specific resistance, a highstability to ultraviolet light and a high stability to heat. Another aimis to provide a liquid crystal composition having a suitable balanceregarding at least two of the characteristics. A further aim is toprovide a liquid crystal display device containing such a composition.An additional aim is to provide a composition having a suitable opticalanisotropy to be a small optical anisotropy or a large opticalanisotropy, a large negative dielectric anisotropy, a high stability toultraviolet light and so forth, and is to provide an AM device having ashort response time, a large voltage holding ratio, a large contrastratio, a long service life and so forth.

Solution to Problem

The invention concerns a liquid crystal composition that has a negativedielectric anisotropy and contains at least one compound selected fromthe group of compounds represented by formula (1) as a first component,at least one compound selected from the group of compounds representedby formula (2) as a second component and at least one compound selectedfrom the group of compounds represented by formula (3) as a thirdcomponent, and concerns a liquid crystal display device

wherein R¹, R², R³ and R⁴ are independently alkyl having 1 to 12carbons, alkoxy having 1 to 12 carbons or alkenyl having 2 to 12carbons, or alkenyl having 2 to 12 carbons in which arbitrary hydrogenis replaced by fluorine; R⁵ and R⁶ are independently alkyl having 1 to12 carbons, alkenyl having 2 to 12 carbons, or alkenyl having 2 to 12carbons in which arbitrary hydrogen is replaced by fluorine; and m is 1or 2.

Effects of Invention

An advantage of the invention is a liquid crystal composition satisfyingat least one of characteristics such as a high maximum temperature of anematic phase, a low minimum temperature of the nematic phase, a smallviscosity, a suitable optical anisotropy, a large negative dielectricanisotropy, a large specific resistance, a high stability to ultravioletlight and a high stability to heat. One aspect of the invention is aliquid crystal composition having a suitable balance regarding at leasttwo of the characteristics. Another aspect is a liquid crystal displaydevice containing such a composition. A further aspect is a compositionhaving a suitable optical anisotropy, a large negative dielectricanisotropy, a high stability to ultraviolet light and so forth, and isan AM device having a short response time, a large voltage holdingratio, a large contrast ratio, a long service life and so forth.

DESCRIPTION OF EMBODIMENTS

The terms used in the specification and claims are defined as follows.The liquid crystal composition of the invention and the liquid crystaldisplay device of the invention may be abbreviated to “the composition”and “the device,” respectively. “A liquid crystal display device” is ageneric term for a liquid crystal display panel and a liquid crystaldisplay module. “A liquid crystal compound” is a generic term for acompound having a liquid crystal phase such as a nematic phase or asmectic phase, and also for a compound having no liquid crystal phasesbut being useful as a component of a composition. Such a useful compoundhas a six-membered ring such as 1,4-cyclohexylene and 1,4-phenylene, anda rod-like molecular structure. An optically active compound and apolymerizable compound may occasionally be added to the composition.Even in the case where these compounds are liquid crystalline, thecompounds are classified as an additive herein. At least one compoundselected from the group of compounds represented by formula (1) may beabbreviated to “the compound (1).” “The compound (1)” means onecompound, or two or more compounds represented by formula (1). The samerules apply to compounds represented by the other formulas. “Arbitrary”is used not only in cases where the position is arbitrary but also incases where the number is arbitrary. However, it is not used in caseswhere the number is 0 (zero).

A higher limit of a temperature range of the nematic phase may beabbreviated as “maximum temperature.” A lower limit of the temperaturerange of the nematic phase may be abbreviated as “minimum temperature.”An expression “a specific resistance is large” means that thecomposition has a large specific resistance at room temperature and alsoat a temperature close to the maximum temperature of the nematic phasein an initial stage, and that the composition has a large specificresistance at room temperature and also at a temperature close to themaximum temperature of the nematic phase even after using the device fora long time. An expression “a voltage holding ratio is large” means thatthe device has a large voltage holding ratio at room temperature andalso at a high temperature in an initial stage, and that the device hasa large voltage holding ratio at room temperature and also at atemperature close to the maximum temperature of the nematic phase evenafter using the device for a long time. When characteristics such as anoptical anisotropy are explained, values obtained according to themeasuring methods described in Examples will be used. A first componentincludes one compound or two or more compounds. A term “a ratio of thefirst component” is expressed as weight percent (% by weight) of thefirst component based on the total weight of the liquid crystalcomposition. A same rule applies to a ratio of the second component andso forth. A ratio of the additive mixed with the composition isexpressed as weight percent (% by weight) or weight parts per million(ppm) based on the total weight of the liquid crystal composition.

The symbol R¹ is used for a plurality of compounds in the chemicalformulas of component compounds. The meanings of R¹ may be the same ordifferent in two of these compounds. In one case, for example, R¹ of thecompound (1) is ethyl and R¹ of the compound (5-1) is ethyl. In anothercase, R¹ of the compound (1) is ethyl and R¹ of the compound (5-1) ispropyl. The same rule applies to the symbols Z², ring E¹ and so forth.

The invention includes the following items.

Item 1. A liquid crystal composition that has a negative dielectricanisotropy and contains at least one compound selected from the group ofcompounds represented by formula (1) as a first component, at least onecompound selected from the group of compounds represented by formula (2)as a second component and at least one compound selected from the groupof compounds represented by formula (3) as a third component:

wherein R¹, R², R³ and R⁴ are independently alkyl having 1 to 12carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbonsor alkenyl having 2 to 12 carbons in which arbitrary hydrogen isreplaced by fluorine; R⁵ and R⁶ are independently alkyl having 1 to 12carbons, alkenyl having 2 to 12 carbons, or alkenyl having 2 to 12carbons in which arbitrary hydrogen is replaced by fluorine; and m is 1or 2.Item 2. The liquid crystal composition according to item 1, wherein R⁵is alkenyl having 2 to 12 carbons in the third component.Item 3. The liquid crystal composition according to item 1 or 2, whereina ratio of the first component is in the range of 5% by weight to 45% byweight, a ratio of the second component is in the range of 5% by weightto 25% by weight, and a ratio of the third component is in the range of10% by weight to 60% by weight based on the total weight of the liquidcrystal composition.Item 4. The liquid crystal composition according to any one of items 1to 3, further containing at least one compound selected from the groupof compounds represented by formula (4) as a fourth component:

wherein R³ and R⁴ are independently alkyl having 1 to 12 carbons, alkoxyhaving 1 to 12 carbons or alkenyl having 2 to 12 carbons, or alkenylhaving 2 to 12 carbons in which arbitrary hydrogen is replaced byfluorine; ring A, ring B are independently 1,4-cyclohexylene,1,4-phenylene; ring C is 1,4-cyclohexylene, 1,4-phenylene,2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene or2,5-difluoro-1,4-phenylene, and at least one of ring A, ring B and ringC is 1,4-phenylene; Z¹ is independently a single bond, ethylene orcarbonyloxy; and j is 0, 1 or 2.Item 5. The liquid crystal composition according to item 4, wherein thefourth component is at least one compound selected from the group ofcompounds represented by formula (4-1) to formula (4-8):

wherein R³ and R⁴ are independently alkyl having 1 to 12 carbons, alkoxyhaving 1 to 12 carbons, alkenyl having 2 to 12 carbons, or alkenylhaving 2 to 12 carbons in which arbitrary hydrogen is replaced byfluorine.Item 6. The liquid crystal composition according to item 5, wherein thefourth component is at least one compound selected from the group ofcompounds represented by formula (4-2).Item 7. The liquid crystal composition according to item 5, wherein thefourth component is at least one compound selected from the group ofcompounds represented by formula (4-3).Item 8. The liquid crystal composition according to item 5, wherein thefourth component is at least one compound selected from the group ofcompounds represented by formula (4-8).Item 9. The liquid crystal composition according to any one of items 4to 8, wherein a ratio of the fourth component is in the range of 5% byweight to 30% by weight based on the total weight of the liquid crystalcomposition.Item 10. The liquid crystal composition according to any one of items 1to 9, further containing at least one compound selected from the groupof compounds represented by formula (5-1) to formula (5-2) as a fifthcomponent:

wherein R¹ and R² are independently alkyl having 1 to 12 carbons, alkoxyhaving 1 to 12 carbons or alkenyl having 2 to 12 carbons, or alkenylhaving 2 to 12 carbons in which arbitrary hydrogen is replaced byfluorine; ring D, ring E and ring F are independently 1,4-cyclohexyleneor 1,4-phenylene; Z² and Z³ are independently a single bond, ethylene,methyleneoxy or carbonyloxy; X¹ and X² are independently fluorine orchlorine; k is 1, 2 or 3; and p and q are independently 0, 1, 2 or 3,and a sum of p and q is 3 or less.Item 11. The liquid crystal composition according to item 10, whereinthe fifth component is at least one compound selected from the group ofcompounds represented by formula (5-1-1) to formula (5-1-3), and formula(5-2-1) to formula (5-2-4):

wherein R¹ and R² are independently alkyl having 1 to 12 carbons, alkoxyhaving 2 to 12 carbons in which arbitrary hydrogen is replaced byfluorine; ring E¹, ring E², ring F¹ and ring F² are independently1,4-cyclohexylene or 1,4-phenylene; and Z² and Z³ are independently asingle bond, ethylene, methyleneoxy or carbonyloxy.Item 12. The liquid crystal composition according to item 11, whereinthe fifth component is at least one compound selected from the group ofcompounds represented by formula (5-1-1).Item 13. The liquid crystal composition according to item 11, whereinthe fifth component is at least one compound selected from the group ofcompounds represented by formula (5-1-2).Item 14. The liquid crystal composition according to item 11, whereinthe fifth component is at least one compound selected from the group ofcompounds represented by formula (5-1-3).Item 15. The liquid crystal composition according to any one of items 10to 14, wherein a ratio of the fifth component is in the range of 5% byweight to 45% by weight based on the total weight of the liquid crystalcomposition.Item 16. The liquid crystal composition according to any one of items 1to 15, wherein a maximum temperature of a nematic phase is 70° C. orhigher, an optical anisotropy (25° C.) at a wavelength of 589 nanometersis 0.08 or more, and a dielectric anisotropy (25° C.) at a frequency of1 kHz is −2 or less.Item 17. A liquid crystal display device, containing the liquid crystalcomposition according to any one of items 1 to 16.Item 18. The liquid crystal display device according to item 17, whereinan operating mode in the liquid crystal display device is a VA mode, anIPS mode or a PSA mode, and a driving mode in the liquid crystal displaydevice is an active matrix mode.

The invention further includes the following items: (1) the composition,further containing the optically active compound; (2) the composition,further containing the additive such as an antioxidant, an ultravioletlight absorber or an antifoaming agent; (3) an AM device containing thecomposition; (4) a device containing the composition, and having a TN,ECB, OCB, IPS, VA or PSA mode; (5) a transmissive device, containing thecomposition; (6) use of the composition as the composition having thenematic phase; and (7) use as an optically active composition preparedby addition of the optically active compound to the composition.

The composition of the invention will be explained in the followingorder. First, a constitution of the component compounds in thecomposition will be explained. Second, main characteristics of thecomponent compounds and main effects of the compounds on the compositionwill be explained. Third, a combination of components in thecomposition, a preferred ratio of the component compounds and the basisthereof will be explained. Fourth, a preferred embodiment of thecomponent compounds will be explained. Fifth, specific examples of thecomponent compounds will be shown. Sixth, the additive that may be mixedwith the composition will be explained. Seventh, methods forsynthesizing the component compounds will be explained. Last, anapplication of the composition will be explained.

First, the constitution of the component compounds in the compositionwill be explained. The composition of the invention is classified intocomposition A and composition B. Composition A may further contain anyother liquid crystal compound, the additive and an impurity. “Any otherliquid crystal compound” means a liquid crystal compound different fromcompound (1), compound (2), compound (3), compound (4), compound (5-1)and compound (5-2). Such a compound is mixed with the composition forthe purpose of further adjusting the characteristics. Of any otherliquid crystal compounds, a cyano compound is preferred to be small inview of stability to heat or ultraviolet light. A further preferredratio of the cyano compound is 0% by weight. The additive includes theoptically active compound, the antioxidant, the ultraviolet lightabsorber, a coloring matter, the antifoaming agent, the polymerizablecompound and a polymerization initiator. The impurity includes acompound mixed in a process such as preparation of the componentcompounds. Even in the case where the compound is liquid crystalline,the compound is classified as the impurity herein.

Composition B consists essentially of compounds selected from the groupof compound (1), compound (2), compound (3), compound (4), compound(5-1) and compound (5-2). A term “essentially” means that thecomposition may also contain the additive and the impurity, but does notcontain any liquid crystal compound different from the compounds.Composition B has a smaller number of components than composition A has.Composition B is preferred to composition A in view of cost reduction.Composition A is preferable to composition B in view of capability offurther adjusting physical properties by mixing any other liquid crystalcompound.

Second, the main characteristics of the component compounds and the maineffects of the compounds on the characteristics of the composition willbe explained. The main characteristics of the component compounds aresummarized in Table 2 on the basis of advantageous effects of theinvention. In Table 2, a symbol L stands for “large” or “high,” a symbolM stands for “medium,” and a symbol S stands for “small” or “low.” Thesymbols L, M and S are classified according to a qualitative comparisonamong the component compounds, and 0 (zero) means “a value is nearlyzero.”

TABLE 2 Characteristics of compounds Compounds Com- Com- Com- Com- Com-pound pound pound pound pound (5-1) (1) (2) (3) (4) (5-2) Maximumtemperature  S-M M S-M S-L   S-M Viscosity M-L S-M S  S-M M-L OpticalAnisotropy M L S M-L  M-L Dielectric Anisotropy   L ¹⁾ 0 0 0   M-L ¹⁾Specific Resistance L L L L L ¹⁾ A value of the dielectric anisotropy isnegative, and the symbol shows small and large of an absolute value.

Upon mixing the component compounds with the composition, the maineffects of the component compounds on the characteristics of thecomposition are as described below. Compound (1) increases an absolutevalue of the dielectric anisotropy. Compound (2) increases the opticalanisotropy. Compound (3) decreases a viscosity. Compound (4) increasesthe maximum temperature or decreases the minimum temperature. Compound(5-1) and compound (5-2) increase the absolute value of the dielectricanisotropy and decreases the minimum temperature.

Third, the combination of the components in the composition, thepreferred ratio of the component compounds and the basis thereof will beexplained. The combination of the components in the composition includesa combination of the first component, the second component and the thirdcomponent, a combination of the first component, the second component,the third component and the fourth component, a combination of the firstcomponent, the second component, the third component and the fifthcomponent and a combination of the first component, the secondcomponent, the third component, the fourth component and the fifthcomponent. A preferred combination of the components in the compositionincludes the combination of the first component, the second component,the third component and the fourth component, and the combination of thefirst component, the second component, the third component, the fourthcomponent and the fifth component.

A preferred ratio of the first component is about 5% by weight or morefor increasing the absolute value of the dielectric anisotropy, andabout 45% by weight or less for decreasing the minimum temperature. Afurther preferred ratio is in the range of about 5% by weight to about40% by weight. A particularly preferred ratio is in the range of about10% by weight to about 35% by weight.

A preferred ratio of the second component is about 5% by weight or morefor increasing the optical anisotropy, and about 25% by weight or lessfor decreasing the minimum temperature. A further preferred ratio is inthe range of about 5% by weight to about 20% by weight. A particularlypreferred ratio is in the range of about 5% by weight to about 15% byweight.

A preferred ratio of the third component is about 10% by weight or morefor decreasing the viscosity, and about 60% or less for increasing theabsolute value of the dielectric anisotropy. A further preferred ratiois in the range of about 15% by weight to about 55% by weight. Aparticularly preferred ratio is in the range of about 20% by weight toabout 50% by weight.

A preferred ratio of the fourth component is about 5% by weight or morefor increasing the maximum temperature or decreasing the minimumtemperature, and about 30% by weight or less for increasing the absolutevalue of the dielectric anisotropy. A further preferred ratio is in therange of about 5% by weight to about 25% by weight. A particularlypreferred ratio is in the range of about 5% by weight to about 20% byweight.

A preferred ratio of the fifth component is about 5% by weight or morefor increasing the absolute value of the dielectric anisotropy, andabout 45% by weight or less for decreasing the viscosity. A furtherpreferred ratio is in the range of about 5% by weight to about 40% byweight. A particularly preferred ratio is in the range of about 5% byweight to about 35% by weight.

Fourth, the preferred embodiment of the component compounds will beexplained. R¹, R², R³ and R⁴ are independently alkyl having 1 to 12carbons, alkoxy having 1 to 12 carbons or alkenyl having 2 to 12carbons, or alkenyl having 2 to 12 carbons in which arbitrary hydrogenis replaced by fluorine. Preferred R¹ or R² is alkyl having 1 to 12carbons for increasing the stability to ultraviolet light or heat, orthe like, or alkoxy having 1 to 12 carbons for increasing the absolutevalue of the dielectric anisotropy. Preferred R³ or R⁴ is alkyl having 1to 12 carbons for increasing the stability to ultraviolet light or heat,or the like, or alkenyl having 2 to 12 carbons for decreasing theminimum temperature. R⁵ and R⁶ are independently alkyl having 1 to 12carbons, alkenyl having 2 to 12 carbons, or alkenyl having 2 to 12carbons in which arbitrary hydrogen is replaced by fluorine. PreferredR⁵ is alkenyl having 2 to 12 carbons for decreasing the minimumtemperature. Preferred R⁶ is alkyl having 1 to 12 carbons for increasingthe stability to ultraviolet light or heat, or the like.

Preferred alkyl is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptylor octyl. Further preferred alkyl is ethyl, propyl, butyl, pentyl orheptyl for decreasing the viscosity.

Preferred alkoxy is methoxy, ethoxy, propoxy, butoxy, pentyloxy,hexyloxy or heptyloxy. Further preferred alkoxy is methoxy or ethoxy fordecreasing the viscosity.

Preferred alkenyl is vinyl, 1-propenyl, 2-propenyl, 1-butenyl,2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl,1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl or 5-hexenyl. Furtherpreferred alkenyl is vinyl, 1-propenyl, 3-butenyl or 3-pentenyl fordecreasing the viscosity. A preferred configuration of —CH═CH— in thealkenyl depends on a position of a double bond. Trans is preferable inthe alkenyl such as 1-propenyl, 1-butenyl, 1-pentenyl, 1-hexenyl,3-pentenyl and 3-hexenyl for decreasing the viscosity, for instance. Cis preferable in the alkenyl such as 2-butenyl, 2-pentenyl and2-hexenyl. In the alkenyl, straight-chain alkenyl is preferred tobranched-chain alkenyl.

Preferred examples of alkenyl in which arbitrary hydrogen is replaced byfluorine include 2,2-difluorovinyl, 3,3-difluoro-2-propenyl,4,4-difluoro-3-butenyl, 5,5-difluoro-4-pentenyl and6,6-difluoro-5-hexenyl. Further preferred examples include2,2-difluorovinyl or 4,4-difluoro-3-butenyl for decreasing theviscosity.

Ring A and ring B are independently 1,4-cyclohexylene or 1,4-phenylene.Ring C is 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene,3-fluoro-1,4-phenylene or 2,5-fluoro-1,4-phenylene, and at least one ofring A, ring B and ring C is 1,4-phenylene. Two of ring C may beidentical or different when j is 2. Preferred ring A, ring B or ring Cis 1,4-cyclohexylene for decreasing the viscosity. Ring D, ring E, ringE¹, ring E², ring F, ring F¹ and ring F² are independently1,4-cyclohexylene or 1,4-phenylene, arbitrary two of ring D may beidentical or different when k is 2 or 3, arbitrary two of ring E may beidentical or different when p is 2 or 3, and arbitrary two of ring F maybe identical or different when q is 2 or 3. Preferred ring D, ring E,ring E¹, ring E², ring F, ring F¹ or ring F² is 1,4-cyclohexylene fordecreasing the optical anisotropy. With regard to a configuration of1,4-cyclohexylene, trans is preferable to cis for increasing the maximumtemperature.

Z¹ is independently a single bond, ethylene or carbonyloxy, and two ofZ¹ may be identical or different when j is 2. Preferred Z¹ is a singlebond for decreasing the viscosity. Z² and Z³ are independently a singlebond, ethylene, methyleneoxy or carbonyloxy, arbitrary two of Z² may beidentical or different when k and p are 2 or 3, and arbitrary two of Z³may be identical or different when q is 2 or 3. Preferred Z² or Z³ is asingle bond for decreasing the viscosity, or methyleneoxy for increasingthe absolute value of the dielectric anisotropy.

X¹ and X² are independently fluorine or chlorine. Preferred X¹ or X² isfluorine for decreasing the viscosity.

Then, m is 1 or 2. Preferred m is 2 for increasing the maximumtemperature. Then, j is 0, 1 or 2. Preferred j is 1 for decreasing theminimum temperature. Herein, k is 1, 2 or 3. Preferred k is 2 fordecreasing the minimum temperature. Thus, p and q are independently 0,1, 2 or 3, and a sum of p and q is 3 or less. Preferred p is 2 forincreasing the maximum temperature. Preferred q is 0 for decreasing theminimum temperature.

Fifth, the specific examples of the component compounds will be shown.In the preferred compounds described below, R⁷ is straight-chain alkylhaving 1 to 12 carbons or straight-chain alkoxy having 1 to 12 carbons.R⁸ and R⁹ are independently straight-chain alkyl having 1 to 12 carbonsor straight-chain alkenyl having 2 to 12 carbons. R¹⁰ is straight-chainalkenyl having 2 to 12 carbons.

Preferred compound (1) includes compound (1-1) and compound (1-2).Further preferred compound (1) includes compound (1-2). Preferredcompound (2) includes compound (2-1). Preferred compound (3) includescompound (3-1). Preferred compound (4) includes compound (4-1-1) tocompound (4-8-1). Further preferred compound (4) includes compound(4-2-1), compound (4-3-1), compound (4-4-1) and compound (4-8-1).Particularly preferred compound (4) includes compound (4-3-1), compound(4-4-1) and compound (4-8-1). Preferred compound (5-1) includes compound(5-1-1-1) to compound (5-1-3-1). Further preferred compound (5-1)includes compound (5-1-1-1) and compound (5-1-2-1). Preferred compound(5-2) includes compound (5-2-1-1), compound (5-2-1-2), compound(5-2-2-1), compound (5-2-3-1) to compound (5-2-3-5), compound (5-2-4-1)and compound (5-2-4-2). Further preferred compound (5-2) includescompound (5-2-1-2), compound (5-2-3-1), compound (5-2-3-3) and compound(5-2-4-1). Particularly preferred compound (5-2) includes compound(5-2-1-2) and compound (5-2-3-3).

Sixth, the additive that may be mixed with the composition will beexplained. Such an additive includes the optically active compound, theantioxidant, the ultraviolet light absorber, the coloring matter, theantifoaming agent, the polymerizable compound and the polymerizationinitiator. The optically active compound is mixed with the compositionfor the purpose of inducing a helical structure and giving a twist anglein liquid crystals. Examples of such a compound include compound (6-1)to compound (6-4). A preferred ratio of the optically active compound is5% by weight or less, and a further preferred ratio is in the range ofabout 0.01% by weight to about 2% by weight.

The antioxidant is mixed with the composition for the purpose ofpreventing a decrease in specific resistance caused by heating in air,or maintaining a large voltage holding ratio at room temperature andalso at a temperature close to the maximum temperature of the nematicphase after using the device for a long time.

Preferred examples of the antioxidant include compound (7) where n is aninteger from 1 to 9. In compound (7), preferred n is 1, 3, 5, 7 or 9.Further preferred n is 1 or 7. Compound (7) where n is 1 is effective inpreventing a decrease in specific resistance caused by heating in airbecause the compound (7) has a large volatility. Compound (7) where n is7 is effective in maintaining a large voltage holding ratio at roomtemperature and also at a temperature close to the maximum temperatureof the nematic phase after using the device for a long time because thecompound (7) has a small volatility. A preferred ratio of theantioxidant is about 50 ppm or more for achieving the effect thereof,and about 600 ppm or less for avoiding a decrease in maximum temperatureor avoiding an increase in minimum temperature. A further preferredratio is in the range of about 100 ppm to about 300 ppm.

Preferred examples of the ultraviolet light absorber include abenzophenone derivative, a benzoate derivative and a triazolederivative. A light stabilizer such as an amine having steric hindranceis also preferred. A preferred ratio of the ultraviolet light absorberor the stabilizer is about 50 ppm or more for achieving the effectthereof, and about 10,000 ppm or less for avoiding a decrease in maximumtemperature or avoiding an increase in minimum temperature. A furtherpreferred ratio is in the range of about 100 ppm to about 10,000 ppm.

A dichroic dye such as an azo dye or an anthraquinone dye is mixed withthe composition to be adapted for a device having a guest host (GH)mode. A preferred ratio of the coloring matter is in the range of about0.01% by weight to about 10% by weight. The antifoaming agent such asdimethyl silicone oil or methyl phenyl silicone oil is mixed with thecomposition for preventing foam formation. A preferred ratio of theantifoaming agent is about 1 ppm or more for achieving the effectthereof, and about 1,000 ppm or less for avoiding a poor display. Afurther preferred ratio is in the range of about 1 ppm to about 500 ppm.

The polymerizable compound is mixed with the composition to be adaptedfor the device having the polymer sustained alignment (PSA) mode.Preferred examples of the polymerizable compound include a compoundhaving a polymerizable group, such as acrylate, methacrylate, vinylcompound, vinyloxy compound, propenyl ether, epoxy compound (oxirane,oxetane) and vinyl ketone. Particularly preferred examples include anacrylate derivative or a methacrylate derivative. A preferred ratio ofthe polymerizable compound is about 0.05% by weight or more forachieving the effect thereof; and about 10% by weight or less foravoiding a poor display. A further preferred ratio is in the range ofabout 0.1% by weight to about 2% by weight. The polymerizable compoundis polymerized by irradiation with ultraviolet light or the like,preferably, in the presence of a suitable initiator such as aphotopolymerization initiator. Suitable conditions for polymerization,suitable types of the initiator and suitable amounts thereof are knownto a person skilled in the art and are described in literatures. Forexample, Irgacure 651 (registered trademark), Irgacure 184 (registeredtrademark) or Darocure 1173 (registered trademark) (Ciba Japan K.K.),each being a photoinitiator, is suitable for radical polymerization. Apreferred ratio of the photopolymerization initiator is in the range ofabout 0.1% by weight to about 5% by weight of the polymerizablecompound, and a particularly preferred ratio is in the range of about 1%by weight to about 3% by weight.

Seventh, the methods for synthesizing the component compounds will beexplained. The compounds can be prepared according to known methods.Compound (1-1) and compound (1-2) are prepared by the method describedin JP H2-503568 A (1990). Compound (2-1) is prepared by the methoddescribed in JP 2006-503130 A. Compound (3-1) is prepared by the methoddescribed in JP S59-176221A (1984). Compound (4-8-1) is prepared by themethod described in JP H2-237949 A (1990). Compound (5-1-1-1) isprepared by the method described in JP H2-503441 A (1990). Compound(5-2-2-1) is prepared by the method described in JP 2005-35986 A (2005).The antioxidant is commercially available. A compound represented byformula (7) where n is 1 is available from Sigma-Aldrich Corporation.Compound (7) where n is 7 and so forth is prepared according to themethod described in U.S. Pat. No. 3,660,505 B.

Any compounds whose synthetic methods are not described above can beprepared according to the methods described in books such as OrganicSyntheses (John Wiley & Sons, Inc.), Organic Reactions (John Wiley &Sons, Inc.), Comprehensive Organic Synthesis (Pergamon Press), NewExperimental Chemistry Course (Shin Jikken Kagaku Koza inJapanese)(Maruzen Co., Ltd.). The composition is prepared according toknown methods using the thus obtained compounds. For example, thecomponent compounds are mixed and dissolved in each other by heating.

Last, the application of the composition will be explained. Thecomposition of the invention mainly has a minimum temperature of about−10° C. or lower, a maximum temperature of about 70° C. or higher, andan optical anisotropy in the range of about 0.07 to about 0.20. Thedevice containing the composition has a large voltage holding ratio. Thecomposition is suitable for use in the AM device. The composition isparticularly suitable for use in a transmissive AM device. Thecomposition having an optical anisotropy in the range of about 0.08 toabout 0.25, and also the composition having an optical anisotropy in therange of about 0.10 to about 0.30 may be prepared by adjusting the ratioof the component compounds or by mixing with any other liquid crystalcompound. The composition can be used as the composition having thenematic phase and as the optically active composition by adding theoptically active compound.

The composition can be used for the AM device, and also for a PM device.The composition can also be used for an AM device and a PM device havinga mode such as PC, TN, STN, ECB, OCB, IPS, VA or PSA. Use for the AMdevice having the IPS or VA mode is particularly preferred. The devicemay be of a reflective type, a transmissive type or a transreflectivetype. Use for the transmissive device is preferred. The composition canbe also used for an amorphous silicon-TFT device or a polycrystalsilicon-TFT device. The composition can be also used for a nematiccurvilinear aligned phase (NCAP) device prepared by microencapsulatingthe composition, and for a polymer dispersed (PD) device in which athree-dimensional network-polymer is formed in the composition.

EXAMPLES

In order to evaluate a composition and a compound to be contained in thecomposition, the composition and the compound were made as a measurementobject. When the measurement object was the composition, the measurementobject was measured as is, and values obtained were described. When themeasurement object was the compound, a sample for measurement wasprepared by mixing the compound (15% by weight) into mother liquidcrystals (85% by weight). Characteristic values of the compound werecalculated from values obtained by measurement, according to anextrapolation method:

(extrapolated value)={(measured value of a sample)−0.85×(measured valueof mother liquid crystals)}/0.15. When a smectic phase (or crystals)precipitated at the ratio thereof at 25° C., a ratio of the compound tothe mother liquid crystals was changed step by step in the order of (10%by weight:90% by weight), (5% by weight:95% by weight) and (1% byweight:99% by weight). Values of a maximum temperature, an opticalanisotropy, a viscosity and a dielectric anisotropy with regard to thecompound were obtained by the extrapolation method.

Components of the mother liquid crystals were as described below. Aratio of each component is weight percent.

17.2%

27.6%

20.7%

20.7%

13.8%

Characteristics were measured according to the methods described below.Most of the methods are applied as described in EIAJ ED-2521A of theStandard of Electronic Industries Association of Japan, or modifiedthereon.

Maximum Temperature of a Nematic Phase (NI; ° C.): A sample was placedon a hot plate in a melting point apparatus equipped with a polarizingmicroscope and was heated at a rate of 1° C. per minute. Temperaturewhen a part of the sample began to change from a nematic phase to anisotropic liquid was measured. A higher limit of a temperature range ofthe nematic phase may be abbreviated as “maximum temperature.”

Minimum Temperature of a Nematic Phase (T_(c); ° C.): A sample having anematic phase was put in glass vials and kept in freezers for 10 days attemperatures of 0° C., −10° C., −20° C., −30° C. and −40° C., and thenliquid crystal phases were observed. For example, when the samplemaintained the nematic phase at −20° C. and changed to crystals or asmectic phase at −30° C., T_(c) was expressed as T_(c)≦−20° C. A lowerlimit of a temperature range of the nematic phase may be abbreviated as“minimum temperature.”

Viscosity (bulk viscosity; η; measured at 20° C.; mPa·s): A cone-plate(E type) viscometer was used for measurement.

Optical Anisotropy (refractive index anisotropy; Δn; measured at 25°C.): Measurement was carried out by means of an Abbe refractometer witha polarizing plate mounted on an ocular, using light at a wavelength of589 nanometers. A surface of a main prism was rubbed in one direction,and then a sample was added dropwise onto the main prism. A refractiveindex (n∥) was measured when the direction of polarized light wasparallel to the direction of rubbing. A refractive index (n⊥) wasmeasured when the direction of polarized light was perpendicular to thedirection of rubbing. A value of optical anisotropy was calculated froman equation: Δn=n∥−n⊥.

Dielectric Anisotropy (Δ∈; measured at 25° C.): A value of dielectricanisotropy was calculated from an equation:

Δ∈=∈∥−∈⊥. A dielectric constant (∈∥ and ∈⊥) was measured as describedbelow.

1) Measurement of dielectric constant (∈∥): An ethanol (20 mL) solutionof octadecyl triethoxysilane (0.16 mL) was applied to a well-washedglass substrate. After rotating the glass substrate with a spinner, theglass substrate was heated at 150° C. for 1 hour. A sample was put in aVA device in which a distance (cell gap) between two glass substrateswas 4 micrometers, and the device was sealed with an ultraviolet-curableadhesive. Sine waves (0.5 V, 1 kHz) were applied to the device, andafter 2 seconds, a dielectric constant (∈∥) in the major axis directionof liquid crystal molecules was measured.2) Measurement of dielectric constant (∈⊥): A polyimide solution wasapplied to a well-washed glass substrate. After calcining the glasssubstrate, rubbing treatment was applied to the alignment film obtained.A sample was put in a TN device in which a distance (cell gap) betweentwo glass substrates was 9 micrometers and a twist angle was 80 degrees.Sine waves (0.5 V, 1 kHz) were applied to the device, and after 2seconds a dielectric constant (∈⊥) in the minor axis direction of theliquid crystal molecules was measured.

Threshold Voltage (Vth; measured at 25° C.; V): An LCD-5100 luminancemeter made by Otsuka Electronics Co., Ltd. was used for measurement. Alight source was a halogen lamp. A sample was put in a VA device havinga normally black mode, in which a distance (cell gap) between two glasssubstrates was 4 micrometers and a rubbing direction was anti-parallel,and the device was sealed with an ultraviolet-curable adhesive. Avoltage to be applied to the device (60 Hz, rectangular waves) wasstepwise increased from 0 V to 20 V at an increment of 0.02 V. On theoccasion, the device was irradiated with light in a perpendiculardirection, and the amount of light passing through the device wasmeasured. A voltage-transmittance curve was prepared, in which themaximum amount of light corresponds to 100% transmittance and theminimum amount of light corresponds to 0% transmittance. A thresholdvoltage is a voltage at 10% transmittance.

Voltage Holding Ratio (VHR-1; measured at 25° C.; %): A TN device usedfor measurement had a polyimide-alignment film, and a distance (cellgap) between two glass substrates was 5 micrometers. A sample was put inthe device, and then the device was sealed with an ultraviolet-curableadhesive. A pulse voltage (60 microseconds at 5 V) was applied to the TNdevice and the device was charged. A decreasing voltage was measured for16.7 milliseconds with a high-speed voltmeter, and area A between avoltage curve and a horizontal axis in a unit cycle was obtained. Area Bis an area without a decrease. A voltage holding ratio is a percentageof area A to area B.

Voltage Holding Ratio (VHR-2; measured at 80° C.; %): A TN device usedfor measurement had a polyimide-alignment film, and a distance (cellgap) between two glass substrates was 5 micrometers. A sample was put inthe device, and then the device was sealed with an ultraviolet-curableadhesive. A pulse voltage (60 microseconds at 5 V) was applied to the TNdevice and the device was charged. A decreasing voltage was measured for16.7 milliseconds with a high-speed voltmeter and area A between avoltage curve and a horizontal axis in a unit cycle was obtained. Area Bis an area without a decrease. A voltage holding ratio is a percentageof area A to area B.

Voltage Holding Ratio (VHR-3; measured at 25° C.; %): Stability toultraviolet light was evaluated by measuring a voltage holding ratioafter irradiation with ultraviolet light. A TN device used formeasurement had a polyimide-alignment film and a cell gap was 5micrometers. A sample was poured into the device, and then the devicewas irradiated with light for 20 minutes. A light source was an ultrahigh-pressure mercury lamp USH-500D (made by Ushio, Inc.), and adistance between the device and the light source was 20 centimeters. Inmeasuring VHR-3, a decreasing voltage was measured for 16.7milliseconds. A composition having a large VHR-3 has a high stability toultraviolet light. A value of VHR-3 is preferably in the range of 90% ormore, further preferably, 95% or more.

Voltage Holding Ratio (VHR-4; measured at 25° C.; %): A TN device intowhich a sample was poured was heated in a constant-temperature bath at80° C. for 500 hours, and then stability to heat was evaluated bymeasuring a voltage holding ratio. In measuring VHR-4, a decreasingvoltage was measured for 16.7 milliseconds. A composition having a largeVHR-4 has a high stability to heat.

Response Time (τ; measured at 25° C.; millisecond): An LCD-5100luminance meter made by Otsuka Electronics Co., Ltd. was used formeasurement. A light source was a halogen lamp. A low-pass filter wasset at 5 kHz. A sample was put in a PVA device having a normally blackmode, in which a distance (cell gap) between two glass substrates was3.2 micrometers and a rubbing direction was anti-parallel. The devicewas sealed with an ultraviolet-curable adhesive. A voltage just over athreshold voltage was applied to the device for about one minute, next,while applying a voltage of 5.6 V, the device was irradiated withultraviolet light at 23.5 mW/cm² for about 8 minutes. Rectangular waves(60 Hz, 10 V, 0.5 second) were applied to the device. On the occasion,the device was irradiated with light in a perpendicular direction, andthe amount of light passing through the device was measured. The maximumamount of light corresponds to 100% transmittance, and the minimumamount of light corresponds to 0% transmittance. A response time is timerequired for a change from 0% transmittance to 90% transmittance (risetime; millisecond).

Specific Resistance (ρ; measured at 25° C.; Ω cm): A sample of 1.0milliliter was put in a vessel equipped with electrodes. A DC voltage(10 V) was applied to the vessel, and a DC current after 10 seconds wasmeasured. A specific resistance was calculated from the followingequation:(specific resistance)={(voltage)×(electric capacity of vessel)}/{(DCcurrent)×(dielectric constant in vacuum)}.

Gas Chromatographic Analysis: GC-14B gas chromatograph made by ShimadzuCorporation was used for measurement. A carrier gas was helium (2 mL perminute). A sample injector and a detector (FID) were set to 280° C. and300° C., respectively. A capillary column DB-1 (length 30 m, bore 0.32mm, film thickness 0.25 μm; dimethylpolysiloxane as a stationary phase,non-polar) made by Agilent Technologies, Inc. was used for separation ofcomponent compounds. After the column was kept at 200° C. for 2 minutes,the column was further heated to 280° C. at a rate of 5° C. per minute.A sample was dissolved in an acetone solution (0.1% by weight), and then1 microliter of the solution was injected into the sample injector. Arecorder used was C-R5A Chromatopac made by Shimadzu Corporation or theequivalent thereof. The resulting gas chromatogram showed a retentiontime of a peak and a peak area corresponding to each of the componentcompounds.

As a solvent for diluting a sample, chloroform, hexane and so forth mayalso be used. The following capillary columns may also be used forseparating component compounds: HP-1 (length 30 m, bore 0.32 mm, filmthickness 0.25 μm) made by Agilent Technologies Inc., Rtx-1 (length 30m, bore 0.32 mm, film thickness 0.25 μm) made by Restek Corporation, andBP-1 (length 30 m, bore 0.32 mm, film thickness 0.25 μm) made by SGEInternational Pty. Ltd. A capillary column CBP1-M50-025 (length 50 m,bore 0.25 mm, film thickness 0.25 μm) made by Shimadzu Corporation mayalso be used for the purpose of avoiding an overlap of peaks of thecompounds.

A ratio of liquid crystal compounds included in a composition may becalculated according to the method as described below. The liquidcrystal compounds can be detected by means of a gas chromatograph. Aratio of peak areas in the gas chromatogram corresponds to a ratio (inthe number of moles) of the liquid crystal compounds. When the capillarycolumns described above were used, a correction coefficient of each ofthe liquid crystal compounds may be regarded as 1 (one). Accordingly, aratio (% by weight) of the liquid crystal compounds was calculated fromthe ratio of the peak areas.

The invention will be explained in detail by way of Examples. Theinvention is not limited by the Examples described below. The compoundsdescribed in Comparative Examples and Examples were expressed as symbolsaccording to definitions in Table 3 below. In Table 3, a configurationof 1,4-cyclohexylene is trans. A parenthesized number next to asymbolized compound in Examples corresponds to the number of thecompound. A symbol (−) means any other liquid crystal compound. A ratio(percentage) of liquid crystal compounds means weight percent (% byweight) based on the total weight of the liquid crystal composition. Theliquid crystal composition further includes an impurity in additionthereto. Last, the characteristic values of the composition weresummarized.

TABLE 3 Method for Description of Compounds using SymbolsR—(A₁)—Z₁- - - -Z_(n)—(A_(n))—R^(′) 1) Left-terminal Group R SymbolC_(n)H_(2n+1)— n- C_(n)H_(2n+1)O— nO— C_(m)H_(2m+1)OC_(n)H_(2n)— mOn-CH₂═CH— V— C_(n)H_(2n+1)—CH═CH— nV— CH₂═CH—C_(n)H_(2n)— Vn-C_(m)H_(2m+1)—CH═CH—C_(n)H_(2n)— mVn- CF₂═CH— VFF— CF₂═CH—C_(n)H_(2n)—VFFn- 2) Right-terminal Group- Symbol —C_(n)H_(2n+1) -n —OC_(n)H_(2n+1)—On —CH═CH₂ —V —CH═CH—C_(n)H_(2n+1) —Vn —C_(n)H_(2n)—CH═CH₂ -nV—OC_(n)H_(2n)—CH═CH₂ —OnV —CH═CF₂ —VFF —COOCH₃ —EMe 3) Bonding Group—Z_(n)— Symbol —C₂H₄— 2 —COO— E —CH═CH— V —C≡C— T —CF₂O— X —CH₂O— 1O 4)Ring Structure —A_(n)— Symbol

H

B

B(F)

B(2F)

B(2F,5F)

B(2F,3F)

B(2F,3F,6Me)

B(2F,3Cl)

Cro(7F,8F) 5) Examples of Description Example 1

Example 2

Example 3

Example 4

Comparative Example 1

From the compositions disclosed in EP 474062 A, Example 1 was selected.The basis of selection is that the composition contains compound (1-1)and compound (1-2). Since bulk viscosity was not described, thecomposition was prepared, and measurement was carried out according tothe method described above. The components and characteristics of thecomposition were as described below.

5-H1OB(2F,3F)—O2 (1-1)  9% 5-H2B(2F,3F)—O2 (2-1) 11% 3-HH1OB(2F,3F)—O2(1-2) 14% 5-HH1OB(2F,3F)—O2 (1-2)  8% 5-HH2B(2F,3F)—O2 (—) 15% 3-HH—O2(—) 10% 3-HH—O3 (—) 12% 5-HH—O1 (—)  9% 5-HH—O2 (—) 12% NI = 80.0° C.;Δn = 0.072; η = 20.5 mPa · s.

Comparative Example 2

From the compositions disclosed in JP 2006-37053 A, Example 1 wasselected. The basis of selection is that the composition containscompound (1-1), compound (1-2), compound (3-1), compound (4-1-1) andcompound (5-2-1-2), and has the smallest bulk viscosity. The componentsand characteristics of the composition were as described below.

2-HH1OB(2F,3F)—O2 (1-2) 10% 3-HH1OB(2F,3F)—O2 (1-2) 12%4-HH1OB(2F,3F)—O2 (1-2) 10% 5-H1OB(2F,3F)—O2 (1-1) 11% 3-H1OCro(7F,8F)-5(5-2-1-2)  5% V—HH-5 (3-1) 20% V2—HH-3 (3-1) 13% 3-HVH-5 (—)  6% 3-HB—O2(4-1-1) 13% NI = 82.1° C.; Δn = 0.075; η = 18.5 mPa · s; Δε = −3.4.

Comparative Example 3

From the compositions disclosed in JP 2006-37054 A, Example 2 wasselected. The basis of selection is that the composition containscompound (1-2), compound (3-1) and compound (4-1-1), and has thesmallest bulk viscosity. The components and characteristics of thecomposition were as described below.

2-HH2B(2F,3F)—O2 (—) 15% 3-HH1OB(2F,3F)—O2 (1-2) 15% 4-HH1OB(2F,3F)—O2(1-2) 15% V—HH-5 (3-1) 20% V2—HH-3 (3-1) 13% V2—BTB—2V (—)  9% 3-HB—O2(4-1-1) 13% NI = 91.2° C.; Δn = 0.095; η = 18.0 mPa · s; Δε = −2.6.

Comparative Example 4

From the compositions disclosed in JP 2006-233182 A, Example 6 wasselected. The basis of selection is that the composition containscompound (1-2), compound (3-1) and compound (4-1-1), and has thesmallest bulk viscosity. The components and characteristics of thecomposition were as described below.

V—HH2B(2F,3F)—O2 (—) 15% 3-HH1OB(2F,3F)—O2 (1-2) 15% 4-HH1OB(2F,3F)—O2(1-2) 15% V—HH-5 (3-1) 20% V2—HH-3 (3-1) 13% V2—BTB—2V (—)  9% 3-HB—O2(4-1-1) 13% NI = 90.8° C.; Δn = 0.096; η = 17.0 mPa · s; Δε = −3.0.

Comparative Example 5

From the compositions disclosed in JP 2007-39639 A, Example 20 wasselected. The basis of selection is that the composition containscompound (1-1) and compound (3-1), and has the smallest bulk viscosity.The components and characteristics of the composition were as describedbelow.

3-H1OB(2F,3F)—O2 (1-1)  8% 5-H1OB(2F,3F)—O2 (1-1) 13% V—HH2B(2F,3F)—O1V(—) 10% V—HH2B(2F,3F)—O1V1 (—)  9% V—HH2B(2F,3F)—O2V (—) 10%V—HH2B(2F,3F)—O3V (—) 10% V—HH-5 (3-1) 20% V2—HH-3 (3-1) 10% 3-HVH-5 (—)10% NI = 78.2° C.; Δn = 0.075; η = 18.3 mPa · s; Δε = −4.6.

Comparative Example 6

From the compositions disclosed in JP 2008-308581 A, Example 1 wasselected. The basis of selection is that the composition containscompound (1-2), compound (3-1), compound (4-2-1), compound (4-3-1),compound (5-1-2-1) and compound (5-2-1-2). The components andcharacteristics of the composition were as described below.

V—HH-3 (3-1) 30%  3-HH2B(2F,3F)—O2 (—) 10%  3-HHB(2F,3F)—O2 (5-1-2-1)10%  3-HH1OB(2F,3F)—O1 (1-2) 4% 3-HH1OB(2F,3F)—O2 (1-2) 9%4-HH1OB(2F,3F)—O1 (1-2) 4% 3-H1OCro(7F,8F)-5 (5-2-1-2) 7%5-H1OCro(7F,8F)-5 (5-2-1-2) 7% V—HHB-1 (4-3-1) 9% 5-BB-1 (4-2-1) 10%  NI= 82.7° C.; Δn = 0.087; η = 19.4 mPa · s; Δε = −3.1.

Example 1

3-H1OB(2F,3F)—O2 (1-1) 5% 5-H1OB(2F,3F)—O2 (1-1) 4% 3-HH1OB(2F,3F)—O2(1-2) 5% 5-HH1OB(2F,3F)—O2 (1-2) 5% 2-BB(F)B-3 (2-1) 5% V—HH-3 (3-1)32%  1V—HH-3 (3-1) 7% 3-HB—O2 (4-1-1) 3% 1V—HBB-2 (4-4-1) 4%3-HHB(2F,3F)—O2 (5-1-2-1) 7% 4-HHB(2F,3F)—O2 (5-1-2-1) 6%5-HHB(2F,3F)—O2 (5-1-2-1) 7% 3-H2Cro(7F,8F)-5 (5-2-1-1) 3%3-H1OCro(7F,8F)-5 (5-2-1-2) 4% 3-HHCro(7F,8F)-5 (5-2-3-1) 3% NI = 85.3°C.; Tc ≦ 20° C.; Δn = 0.085; η = 10.9 mPa · s; Δε = −2.7; τ = 8.6 ms;VHR-1 = 99.0%; VHR-2 = 98.0%; VHR-3 = 98.1%.

Example 2

3-H1OB(2F,3F)—O2 (1-1) 5% 5-H1OB(2F,3F)—O2 (1-1) 5% 3-HH1OB(2F,3F)—O2(1-2) 5% 1-BB(F)B—2V (2-1) 5% V—HH-3 (3-1) 40%  3-HHEBH-5 (4-5-1) 3%V—HB(2F,3F)—O2 (5-1-1-1) 5% 3-HHB(2F,3F)—O2 (5-1-2-1) 7% 4-HHB(2F,3F)—O2(5-1-2-1) 6% 5-HHB(2F,3F)—O2 (5-1-2-1) 7% 3-H2Cro(7F,8F)-3 (5-2-1-1) 3%3-H2Cro(7F,8F)-5 (5-2-1-1) 3% 2O—Cro(7F,8F)HH-5 (5-2-4-1) 3%3-Cro(7F,8F)2HH-5 (5-2-4-2) 3% NI = 81.7° C.; Tc ≦ −20° C.; Δn = 0.080;η = 11.1 mPa · s; Δε = −2.7; τ = 8.6 ms; VHR-1 = 99.0%; VHR-2 = 98.1%;VHR-3 = 98.1%.

Example 3

3-HH1OB(2F,3F)—O2 (1-2) 6% 5-HH1OB(2F,3F)—O2 (1-2) 6% V2—BB(F)B-1 (2-1)5% 3-HH—VFF (3) 3% V—HH-3 (3-1) 28%  1V2—BB-1 (4-2-1) 4% 3-HHEBH-5(4-5-1) 3% 3-HB(2F,3F)—O2 (5-1-1-1) 12%  5-HB(2F,3F)—O2 (5-1-1-1) 11% 3-HHB(2F,3F)—O2 (5-1-2-1) 8% 5-HHB(2F,3F)—O2 (5-1-2-1) 8%3-HH1OCro(7F,8F)-5 (5-2-3-3) 6% NI = 82.8° C.; Tc ≦ −20° C.; Δn = 0.088;η = 11.9 mPa · s; Δε = −2.7; τ = 8.7 ms; VHR-1 = 99.1%; VHR-2 = 98.1%;VHR-3 = 98.1%.

Example 4

3-H1OB(2F,3F)—O2 (1-1) 4% 5-H1OB(2F,3F)—O2 (1-1) 4% V—HH1OB(2F,3F)—O2(1-2) 6% 3-HH1OB(2F,3F)—O2 (1-2) 5% 5-HH1OB(2F,3F)—O2 (1-2) 5%V2—BB(F)B-1 (2-1) 4% V2—BB(F)B-2 (2-1) 4% 3-HH—VFF (3) 5% V—HH-3 (3-1)22%  VFF—HHB-1 (4-3) 3% VFF2—HHB-1 (4-3) 3% V2—BB-1 (4-2-1) 4%3-HB(2F,3F)—O2 (5-1-1-1) 7% 5-HB(2F,3F)—O2 (5-1-1-1) 7% 3-HHB(2F,3F)—O2(5-1-2-1) 6% 2-Cro(7F,8F)2H-3 (5-2-2-1) 3% 2O-Cro(7F,8F)2H-3 (5-2-2-1)3% 3-HH1OCro(7F,8F)-5 (5-2-3-3) 5% NI = 72.7° C.; Tc ≦ −20° C.; Δn =0.093; η = 13.2 mPa · s; Δε = −2.7; τ = 8.8 ms; VHR-1 = 99.1%; VHR-2 =98.1%; VHR-3 = 98.1%.

Example 5

V—H1OB(2F,3F)—O4 (1-1) 7% 3-H1OB(2F,3F)—O2 (1-1) 7% 5-H1OB(2F,3F)—O2(1-1) 7% V—HH1OB(2F,3F)—O4 (1-2) 6% 3-HH1OB(2F,3F)—O2 (1-2) 6%1-BB(F)B—2V (2-1) 7% V—HH-3 (3-1) 24%  7-HB-1 (4-1-1) 3% 3-HHB-3 (4-3-1)3% V2—HHB-1 (4-3-1) 3% 3-HHB(2F,3F)—O2 (5-1-2-1) 9% 5-HHB(2F,3F)—O2(5-1-2-1) 9% 3-HH—O1 (—) 3% 3-HHEH-5 (—) 3% 1O1—HBBH-5 (—) 3% NI = 91.0°C.; Tc ≦ −20° C.; Δn = 0.090; η = 13.0 mPa · s; Δε = −2.7; τ = 8.8 ms;VHR-1 = 99.1%; VHR-2 = 98.1%; VHR-3 = 98.2%.

Example 6

3-H1OB(2F,3F)—O2 (1-1) 6% 5-H1OB(2F,3F)—O2 (1-1) 6% 3-HH1OB(2F,3F)—O2(1-2) 6% 4-HH1OB(2F,3F)—O2 (1-2) 5% 5-HH1OB(2F,3F)—O2 (1-2) 5%2-BB(F)B-3 (2-1) 6% 1-BB(F)B—2V (2-1) 6% V—HH-3 (3-1) 20%  V—HH-5 (3-1)5% 1V2—BB-1 (4-2-1) 5% 5-HBBH-3 (4-6-1) 3% 5-HBB(2F)H-3 (4-7-1) 3%V—HB(2F,3F)—O2 (5-1-1-1) 8% V—HB(2F,3F)—O4 (5-1-1-1) 7% 3-HHB(2F,3F)—O2(5-1-2-1) 4% 3-H2Cro(7F,8F)-5 (5-2-1-1) 5% NI = 70.4° C.; Tc ≦ −20° C.;Δn = 0.102; η = 13.7 mPa · s; Δε = −2.8; τ = 8.9 ms; VHR-1 = 99.0%;VHR-2 = 98.1%; VHR-3 = 98.2%.

Example 7

3-H1OB(2F,3F)—O2 (1-1) 8% 4-H1OB(2F,3F)—O2 (1-1) 5% 5-H1OB(2F,3F)—O2(1-1) 8% 3-HH1OB(2F,3F)—O2 (1-2) 7% 5-HH1OB(2F,3F)—O2 (1-2) 5%2-BB(F)B-3 (2-1) 6% 2-BB(F)B-5 (2-1) 6% 2-HH-3 (3) 5% V—HH-3 (3-1) 30% V—HHB-1 (4-3-1) 5% 5-HBB(F)B-2 (4-8-1) 3% 5-HBB(F)B-3 (4-8-1) 3%3-HH2Cro(7F,8F)-5 (5-2-3-2) 3% 3-HBCro(7F,8F)-5 (5-2-3-4) 3%3-BBCro(7F,8F)-5 (5-2-3-5) 3% NI = 83.7° C.; Tc ≦ −20° C.; Δn = 0.109; η= 12.7 mPa · s; Δε = −2.6; τ = 8.8 ms; VHR-1 = 99.1%; VHR-2 = 98.0%;VHR-3 = 98.2%.

Example 8

V—H1OB(2F,3F)—O3 (1-1) 5% 3-HH1OB(2F,3F)—O2 (1-2) 6% 4-HH1OB(2F,3F)—O2(1-2) 6% 5-HH1OB(2F,3F)—O2 (1-2) 6% 1-BB(F)B—2V (2-1) 6% V—HH-3 (3-1)27%  1V—HH-3 (3-1) 5% 3-HHB-1 (4-3-1) 7% 3-HHB—O1 (4-3-1) 4%3-HB(2F,3F)—O2 (5-1-1-1) 5% 3-HB(2F,3F)—O4 (5-1-1-1) 6% V—HHB(2F,3F)—O2(5-1-2-1) 5% V2—HHB(2F,3F)—O2 (5-1-2-1) 5% 3-HHB(2F,3Cl)—O2 (5-1-3-1) 3%4-HHB(2F,3Cl)—O2 (5-1-3-1) 2% 5-HHB(2F,3Cl)—O2 (5-1-3-1) 2% NI = 94.3°C.; Tc ≦ −20° C.; Δn = 0.090; η = 10.7 mPa · s; Δε = −2.8; Vth = 2.57 V;τ = 8.5 ms; VHR-1 = 99.0%; VHR-2 = 98.1%; VHR-3 = 98.0%.

Example 9

3-H1OB(2F,3F)—O2 (1-1) 6% 5-H1OB(2F,3F)—O2 (1-1) 6% 3-HH1OB(2F,3F)—O1(1-2) 3% 3-HH1OB(2F,3F)—O2 (1-2) 4% 1-BB(F)B—2V (2-1) 5% 3-BB(F)B—2V(2-1) 5% V—HH-3 (3-1) 25%  1V—HH-3 (3-1) 7% 5-HB—O2 (4-1-1) 3% 1V—HBB-2(4-4-1) 4% 3-HB(2F,3F)—O2 (5-1-1-1) 7% 3-HHB(2F,3F)—O2 (5-1-2-1) 10% 5-HHB(2F,3F)—O2 (5-1-2-1) 5% 3-H2Cro(7F,8F)-5 (5-2-1-1) 3%3-H1OCro(7F,8F)-5 (5-2-1-2) 4% 3-HHCro(7F,8F)-5 (5-2-3-1) 3% NI = 78.6°C.; Tc ≦ −20° C.; Δn = 0.095; η = 12.4 mPa · s; Δε = −2.4; τ = 8.8 ms;VHR-1 = 99.1%; VHR-2 = 98.1%; VHR-3 = 98.1%.

The compositions according to Examples 1 to 9 have a smaller bulkviscosity in comparison with the compositions according to ComparativeExample 1 to 6. Thus, the liquid crystal composition of the invention isso much superior in characteristics to the compositions shown in thepatent literatures No. 1 to No. 6.

INDUSTRIAL APPLICABILITY

The invention provides a liquid crystal composition satisfying at leastone of characteristics such as a high maximum temperature of a nematicphase, a low minimum temperature of the nematic phase, a smallviscosity, a large optical anisotropy, a large dielectric anisotropy, alarge specific resistance, a high stability to ultraviolet light and ahigh stability to heat, or provides a liquid crystal composition havinga suitable balance regarding at least two of the characteristics. Aliquid crystal display device containing such a liquid crystalcomposition is applied as an AM device having a short response time, alarge voltage holding ratio, a large contrast ratio, a long service lifeand so forth, and thus can be used for a liquid crystal projector, aliquid crystal television and so forth.

What is claimed is:
 1. A liquid crystal composition that has a negativedielectric anisotropy and contains at least one compound selected fromthe group of compounds represented by formula (1) as a first component,at least one compound selected from the group of compounds representedby formula (2) as a second component and at least one compound selectedfrom the group of compounds represented by formula (3) as a thirdcomponent, wherein a ratio of the first component is 10% by weight ormore based on the total weight of the liquid crystal composition:

wherein R¹, R², R³ and R⁴ are independently alkyl having 1 to 12carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbonsor alkenyl having 2 to 12 carbons in which arbitrary hydrogen isreplaced by fluorine; R⁵ and R⁶ are independently alkyl having 1 to 12carbons, alkenyl having 2 to 12 carbons, or alkenyl having 2 to 12carbons in which arbitrary hydrogen is replaced by fluorine; and m is 1or
 2. 2. The liquid crystal composition according to claim 1, wherein aratio of the first component is in the range of 10% by weight to 45% byweight, a ratio of the second component is in the range of 5% by weightto 25% by weight, and a ratio of the third component is in the range of10% by weight to 60% by weight based on the total weight of the liquidcrystal composition.
 3. The liquid crystal composition according toclaim 1, further containing at least one compound selected from thegroup of compounds represented by formula (4) as a fourth component:

wherein R³ and R⁴ are independently alkyl having 1 to 12 carbons, alkoxyhaving 1 to 12 carbons or alkenyl having 2 to 12 carbons, or alkenylhaving 2 to 12 carbons in which arbitrary hydrogen is replaced byfluorine; ring A, ring B are independently 1,4-cyclohexylene,1,4-phenylene; ring C is 1,4-cyclohexylene, 1,4-phenylene,2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene or2,5-difluoro-1,4-phenylene, and at least one of ring A, ring B and ringC is 1,4-phenylene; Z¹ is independently a single bond, ethylene orcarbonyloxy; and j is 0, 1 or
 2. 4. The liquid crystal compositionaccording to claim 3, wherein the fourth component is at least onecompound selected from the group of compounds represented by formula(4-1) to formula (4-8):

wherein R³ and R⁴ are independently alkyl having 1 to 12 carbons, alkoxyhaving 1 to 12 carbons, alkenyl having 2 to 12 carbons, or alkenylhaving 2 to 12 carbons in which arbitrary hydrogen is replaced byfluorine.
 5. The liquid crystal composition according to claim 3,wherein a ratio of the fourth component is in the range of 5% by weightto 30% by weight based on the total weight of the liquid crystalcomposition.
 6. The liquid crystal composition according to claim 1,further containing at least one compound selected from the group ofcompounds represented by formula (5-1) to formula (5-2) as a fifthcomponent:

wherein R¹ and R² are independently alkyl having 1 to 12 carbons, alkoxyhaving 1 to 12 carbons or alkenyl having 2 to 12 carbons, or alkenylhaving 2 to 12 carbons in which arbitrary hydrogen is replaced byfluorine; ring D, ring E and ring F are independently 1,4-cyclohexyleneor 1,4-phenylene; Z² and Z³ are independently a single bond, ethylene,methyleneoxy or carbonyloxy; X¹ and X² are independently fluorine orchlorine; k is 1, 2 or 3; and p and q are independently 0, 1, 2 or 3,and a sum of p and q is 3 or less.
 7. The liquid crystal compositionaccording to claim 6, wherein the fifth component is at least onecompound selected from the group of compounds represented by formula(5-1-1) to formula (5-1-3), and formula (5-2-1) to formula (5-2-4):

wherein R¹ and R² are independently alkyl having 1 to 12 carbons, alkoxyhaving 2 to 12 carbons in which arbitrary hydrogen is replaced byfluorine; ring E¹, ring E², ring F′ and ring F² are independently1,4-cyclohexylene or 1,4-phenylene; and Z² and Z³ are independently asingle bond, ethylene, methyleneoxy or carbonyloxy.
 8. The liquidcrystal composition according to claim 6, wherein a ratio of the fifthcomponent is in the range of 5% by weight to 45% by weight based on thetotal weight of the liquid crystal composition.
 9. The liquid crystalcomposition according to claim 1, wherein a maximum temperature of anematic phase is 70° C. or higher, an optical anisotropy (25° C.) at awavelength of 589 nanometers is 0.08 or more, and a dielectricanisotropy (25° C.) at a frequency of 1 kHz is −2 or less.
 10. A liquidcrystal display device, containing the liquid crystal compositionaccording to claim
 1. 11. The liquid crystal display device according toclaim 10, wherein an operating mode in the liquid crystal display deviceis a VA mode, an IPS mode or a PSA mode, and a driving mode in theliquid crystal display device is an active matrix mode.
 12. The liquidcrystal composition according to claim 3, further containing at leastone compound selected from the group of compounds represented by formula(5-1) to formula (5-2) as a fifth component:

wherein R¹ and R² are independently alkyl having 1 to 12 carbons, alkoxyhaving 1 to 12 carbons or alkenyl having 2 to 12 carbons, or alkenylhaving 2 to 12 carbons in which arbitrary hydrogen is replaced byfluorine; ring D, ring E and ring F are independently 1,4-cyclohexyleneor 1,4-phenylene; Z² and Z³ are independently a single bond, ethylene,methyleneoxy or carbonyloxy; X¹ and X² are independently fluorine orchlorine; k is 1, 2 or 3; and p and q are independently 0, 1, 2 or 3,and a sum of p and q is 3 or less.
 13. The liquid crystal compositionaccording to claim 12, wherein the fifth component is at least onecompound selected from the group of compounds represented by formula(5-1-1) to formula (5-1-3), and formula (5-2-1) to formula (5-2-4):

wherein R¹ and R² are independently alkyl having 1 to 12 carbons, alkoxyhaving 2 to 12 carbons in which arbitrary hydrogen is replaced byfluorine; ring E¹, ring E², ring F′ and ring F² are independently1,4-cyclohexylene or 1,4-phenylene; and Z² and Z³ are independently asingle bond, ethylene, methyleneoxy or carbonyloxy.
 14. The liquidcrystal composition according to claim 12, wherein a ratio of the fifthcomponent is in the range of 5% by weight to 45% by weight based on thetotal weight of the liquid crystal composition.